CN104297695A - Detecting method for capacity of storage battery - Google Patents

Abstract

The invention discloses a detecting method for the capacity of a storage battery. The method comprises the following steps: applying double-pulse current signals to the storage battery, measuring the voltage response and a first derivative generated by the double-pulse current signals at different moments, calculating the change of the electromotive force of the power source of the storage battery and the capacitance and the resistance on a pole plate of the battery plate by using different formulas, and further calculating the capacity of the storage battery. Through the method, the double-pulse current signals are applied to both terminals of the storage battery, the capacity of the storage battery can be detected without discharge of the storage battery, and through certification, the detected result is accurate and reliable.

Description

A kind of detection method of accumulator capacity

Technical field

The present invention relates to a kind of detection method of accumulator capacity, the method does not need to carry out electric discharge to accumulator just can detect accumulator capacity.

Background technology

Further severe along with the day by day in short supply of the energy and environmental pollution, electric automobile, with its superior environmental protection and energy conservation characteristic, becomes the focus of auto industry research, exploitation and utilization.An important motivity ingredient of electric automobile is battery and charging module thereof, and the development of height on ev industry of its technical merit has extremely important impact.

Accumulator is as the main flow battery of electric automobile, and when determining its charging strategy, the capacity of accumulator itself has very important impact.So need in its pre-charging stage determination accumulator capacity.The detection method of traditional storage battery capacity needs to carry out discharge test to accumulator, general operation more complicated, and required chronic.

Summary of the invention

The object of the invention is, in order to overcome deficiency of the prior art, to propose a kind of detection method of accumulator capacity.The method does not need just can detect accumulator capacity to battery discharging, and measure simple, detection speed is fast, and comparatively accurate by repeated detection result.

For achieving the above object, the present invention's openly following technical scheme:

A kind of detection method of accumulator capacity, is characterized in that, comprise the steps:

(1) accumulators applies a pair of pulsed current signal, and the amplitude of dipulse current signal is I, and the dutycycle of dipulse current signal is 50%, and the pulse width of dipulse current signal is T; Define the following moment: initial time t ₀; Dipulse current signal rises to the moment t of I from 0 ₁; The moment t that dipulse current signal declines from I ₂; Dipulse current signal drops to the moment t of 0 from I ₃; The moment t that dipulse current signal rises again from 0 ₄; Dipulse current signal rises to the moment t of I again from 0 ₅; Dipulse current signal starts the moment t declined again ₆;

(2) t is measured respectively ₀, t ₁, t ₂, t ₃, t ₄, t ₅, t ₆the voltage responsive value E of each correspondence that moment dipulse current signal produces ₀, U ₁, U ₂, U ₃, U ₄, U ₅, U ₆and corresponding first order derivative dE ₀/ dt ₀, dU ₁/ dt ₁, dU ₂/ dt ₂, dU ₃/ dt ₃, dU ₄/ dt ₄, dU ₅/ dt ₅, dU ₆/ dt ₆;

(3) utilize the electric capacity on the electromotive force of source of different formulas calculating accumulator, accumulator plate and resistance, and then calculate accumulator capacity:

1) electric capacity on accumulator plate is averaged by three calculating, and calculation equation is:

$C_1=\frac{I}{{\mathrm{dU}}_1/d{t}_1}$ Equation one

In formula: C ₁represent t ₁electric capacity on moment accumulator plate, I represents the amplitude of current impulse;

$C_2=\frac{I}{\frac{{\mathrm{dU}}_2}{{\mathrm{dt}}_2}-\frac{{\mathrm{dU}}_3}{{\mathrm{dt}}_3}}$ Equation two

In formula: C ₂represent t ₃electric capacity on moment accumulator plate, I represents the amplitude of current impulse;

$C_3=\frac{I}{\frac{{\mathrm{dU}}_5}{{\mathrm{dt}}_5}-\frac{{\mathrm{dU}}_4}{{\mathrm{dt}}_4}}$ Equation three

In formula: C ₃represent t ₅electric capacity on moment accumulator plate, I represents the amplitude of current impulse;

By the result of calculation of equation one, equation two and equation three, get its mean value:

C=(C ₁+ C ₂+ C ₃)/3 equation four

The electric capacity C on accumulator plate accurately can be obtained according to equation four;

2) calculation equation of the resistance on accumulator plate is:

$R=\frac{U_3-U_4}{I-(\frac{{\mathrm{dU}}_2}{{\mathrm{dt}}_2}-\frac{{\mathrm{dU}}_4}{{\mathrm{dt}}_4})\×C}$ Equation five

3) variable quantity of the electromotive force of source of accumulator is averaged by secondary calculating, and equation is:

${\mathrm{\ΔE}}_1=U_2-U_1-(I-\frac{{\mathrm{dU}}_2}{{\mathrm{dt}}_2}\×C)\×R$ Equation six

In formula: Δ E ₁represent t ₁moment is to t ₂the variable quantity of the electromotive force of source of moment accumulator;

${\mathrm{\ΔE}}_2=U_6-U_5-(\frac{{\mathrm{dU}}_5}{{\mathrm{dt}}_5}-\frac{d{U}_6}{{\mathrm{dt}}_6})\×C\×R$ Equation seven

In formula: Δ E ₂represent t ₅moment is to t ₆the variable quantity of the electromotive force of source of moment accumulator;

The result of calculation of equation five and equation six is got its mean value:

$\mathrm{\ΔE}=\frac{{\mathrm{\ΔE}}_1+{\mathrm{\ΔE}}_2}{2}$ Equation eight

The electromotive force of source variation delta E of accumulator accurately can be obtained according to equation eight;

(4) calculating accumulator capacity:

$\mathrm{SOC}=\frac{E_0+2\mathrm{\ΔE}-U^{*}+\mathrm{\ΔU}}{\mathrm{\ΔU}}$ Equation nine

In formula: SOC represents accumulator capacity, E ₀represent the initial electromotive force of accumulator, i.e. t ₀the magnitude of voltage that moment surveys, U ^*represent the specification voltage of accumulator, the variable quantity of its electromotive force of source when Δ U represents that accumulator becomes sky electricity from Full Charge Capacity, its expression formula as shown in the formula:

$\mathrm{\ΔU}=\frac{\mathrm{\ΔE}\×\mathrm{AH}}{I\×T}$ Equation ten

In formula: AH represents the specification capacity of accumulator, and I represents the amplitude of dipulse current signal, and T represents the pulse width of dipulse current signal.

Compared with prior art, tool of the present invention has the following advantages:

1. adopt and directly apply dipulse current signal at accumulator two ends, measure its voltage responsive produced and first order derivative, then by can be calculated accumulator parameter, test process and computation process all simple and fasts.

2. by measuring multiple not result in the same time, can repeatedly calculating accumulator parameter, thus make the testing result of accumulator capacity more accurate.

3. the present invention does not need to carry out electric discharge to accumulator and just can detect its capacity, and before and after accumulator testing, capacity remains unchanged substantially.

Accompanying drawing explanation

Fig. 1 is the testing process schematic diagram of accumulator capacity of the present invention;

Fig. 2 is the schematic equivalent circuit of accumulator of the present invention;

Fig. 3 is the schematic diagram of dipulse current signal of the present invention;

Fig. 4 is the battery tension family curve schematic diagram that the present invention detects;

Fig. 5 is embodiment of the present invention detection architecture schematic diagram.

Embodiment

Below in conjunction with accompanying drawing, embodiments of the present invention are described in detail, but are to be understood that protection scope of the present invention not by the restriction of embodiment.

The flow process of the detection method of accumulator capacity of the present invention is as shown in Figure 1:

(1) accumulators applies a pair of pulsed current signal, definition wherein several moment;

(2) voltage responsive and the first order derivative thereof of this dipulse current signal generation is in the same time measured not;

(3) according to the measurement result in step (2), the electric capacity on the electromotive force of source of different formulas calculating accumulator, accumulator plate and resistance is utilized;

(4) electric capacity on the electromotive force of source of the accumulator obtained to (3) according to step (1), accumulator plate and the result calculating accumulator capacity of resistance.

Due to the electrophysics characteristic that accumulator itself has, an accumulator equivalence can be become the circuit shown in Fig. 2.In Fig. 2, E represents storage battery kinetic potential, R ₁represent the conducting resistance of accumulator, R ₂represent the resistance on accumulator plate, C represents the electric capacity on accumulator plate.From the electrochemical properties of accumulator, between accumulator capacity and above several parameter, there is certain corresponding relation.

As shown in Figure 1, (1) accumulators applies a pair of pulsed current signal, several moment of definition: initial time t ₀; Dipulse current signal rises to the moment t of I from 0 ₁; The moment t that dipulse current signal declines from I ₂; Dipulse current signal drops to the moment t of 0 from I ₃; The moment t that dipulse current signal rises again from 0 ₄; Dipulse current signal rises to the moment t of I again from 0 ₅; Dipulse current signal starts the moment t declined again ₆; As shown in Figure 3.

(2) utilization detects the voltage responsive and first order derivative thereof that do not produce in the same time, can draw volt-ampere characteristic curve schematic diagram as shown in Figure 4.

(3) calculation equation of the electric capacity on accumulator plate is:

$C_1=\frac{I}{{\mathrm{dU}}_1/d{t}_1}$ ... equation one

In formula: C ₁represent the electric capacity on accumulator plate, I represents the amplitude of current impulse, dU ₁/ dt ₁represent t ₁moment survey the first derivative values of voltage.

$C_3=\frac{I}{\frac{{\mathrm{dU}}_5}{{\mathrm{dt}}_5}-\frac{{\mathrm{dU}}_4}{{\mathrm{dt}}_4}}$ ... equation two

In formula: C ₂represent the electric capacity on accumulator plate, I represents the amplitude of current impulse, represent t ₂moment survey the first order derivative of voltage, represent t ₃moment survey the first derivative values of voltage.

$C_3=\frac{I}{\frac{{\mathrm{dU}}_5}{{\mathrm{dt}}_5}-\frac{{\mathrm{dU}}_4}{{\mathrm{dt}}_4}}$ ... equation three

In formula: C ₃represent the electric capacity on accumulator plate, I represents the amplitude of current impulse, represent t ₄moment survey the first order derivative of voltage, represent t ₅moment survey the first derivative values of voltage.

According to the result of calculation of equation one, equation two and equation three, get its mean value, expression formula is as follows:

C=(C ₁+ C ₂+ C ₃)/3...... equation four

In formula: C represents the mean value of the electric capacity on accumulator plate, C ₁, C ₂, C ₃represent the electric capacity on the accumulator plate that calculates according to not measurement result in the same time respectively.

The electric capacity C on accumulator plate accurately can be obtained according to equation four.

The calculation equation of the resistance on accumulator plate is:

$R=\frac{U_3-U_4}{I-(\frac{{\mathrm{dU}}_2}{{\mathrm{dt}}_2}-\frac{{\mathrm{dU}}_4}{{\mathrm{dt}}_4})\×C}$ ... equation five

In formula: R represents the resistance on accumulator plate, U ₃represent t ₃the voltage that moment surveys, U ₄represent t ₄the voltage that moment surveys, I represents the amplitude of current impulse, and C represents the electric capacity on accumulator plate, represent t ₂moment survey the first order derivative of voltage, represent t ₄moment survey the first derivative values of voltage.

According to the result of calculation of equation five, the resistance R on accumulator plate can be obtained.

The calculation equation of the variable quantity of the electromotive force of source of accumulator is:

${\mathrm{\ΔE}}_1=U_2-U_1-(I-\frac{{\mathrm{dU}}_2}{{\mathrm{dt}}_2}\×C)\×R$ ... equation six

In formula: Δ E ₁represent the variable quantity of the electromotive force of source of accumulator, U ₁represent t ₁the magnitude of voltage that moment surveys, U ₂represent t ₂the magnitude of voltage that moment surveys, I represents the amplitude of current impulse, and C represents the electric capacity on accumulator plate, and R represents the resistance on accumulator plate, represent t ₂moment survey the first derivative values of voltage.

${\mathrm{\ΔE}}_2=U_6-U_5-(\frac{{\mathrm{dU}}_5}{{\mathrm{dt}}_5}-\frac{d{U}_6}{{\mathrm{dt}}_6})\×C\×R$ ... equation seven

In formula: Δ E ₂represent the variable quantity of the electromotive force of source of battery, U ₅represent t ₅the magnitude of voltage that moment surveys, U ₆represent t ₆the magnitude of voltage that moment surveys, C represents the electric capacity on battery pole plates, and R represents the resistance on battery pole plates, represent t ₅moment survey the first order derivative of voltage, represent t ₆moment survey the first order derivative of voltage.

According to the result of calculation of equation five and equation six, get its mean value, expression formula is as follows:

$\mathrm{\ΔE}=\frac{{\mathrm{\ΔE}}_1+{\mathrm{\ΔE}}_2}{2}$ ... equation eight

In formula: Δ E represents the mean value of the electromotive force of source variable quantity of accumulator, Δ E ₁, Δ E ₂represent the electromotive force of source variable quantity of the accumulator calculated according to not measurement result in the same time respectively.

The electromotive force of source variation delta E of accumulator accurately can be obtained according to equation eight.

Resistance on the electromotive force of source variable quantity of accumulator capacity and accumulator, accumulator plate and the relation between electric capacity can be calculated by following equation:

$\mathrm{SOC}=\frac{E_0+2\mathrm{\ΔE}-U^{*}+\mathrm{\ΔU}}{\mathrm{\ΔU}}$ ... equation nine

In formula: SOC represents accumulator capacity, E ₀represent the initial electromotive force of accumulator, i.e. t ₀the magnitude of voltage that moment surveys, Δ E represents the electromotive force of source variable quantity of accumulator, U ^*represent the specification voltage of accumulator, the variable quantity of its electromotive force of source when Δ U represents that accumulator becomes sky electricity from Full Charge Capacity, its expression formula as shown in the formula:

$\mathrm{\ΔU}=\frac{\mathrm{\ΔE}\×\mathrm{AH}}{I\×T}$ ... equation ten

In formula: Δ E represents the electromotive force of source variable quantity of accumulator, AH represents the specification capacity of accumulator, and I represents the amplitude of dipulse current signal, and T represents the pulse width of dipulse current signal.

Therefore, equation nine and equation ten is utilized accurately can to obtain accumulator capacity.The present invention utilizes measurement result repeatedly, makes the testing result of last accumulator capacity more accurate.

Fig. 5 measures structure for the one of detection method of accumulator capacity of the present invention, and those skilled in the art utilize prior art to realize.

In order to prove correctness and the performance thereof of the inventive method, first by the inventive method, one accumulator capacity is detected, then accumulator is discharged, traditional method is utilized to detect the capacity of this accumulator, finally compare the testing result of two kinds of methods, find that the testing result of the inventive method is identical with the testing result of classic method.

Claims (1)

1. a detection method of accumulator capacity, is characterized in that, comprises the steps:

(1) accumulators applies a pair of pulsed current signal, and the amplitude of dipulse current signal is I, and the dutycycle of dipulse current signal is 50%, and the pulse width of dipulse current signal is T; Define the following moment: initial time t ₀; Dipulse current signal rises to the moment t of I from 0 ₁; The moment t that dipulse current signal declines from I ₂; Dipulse current signal drops to the moment t of 0 from I ₃; The moment t that dipulse current signal rises again from 0 ₄; Dipulse current signal rises to the moment t of I again from 0 ₅; Dipulse current signal starts the moment t declined again ₆;

(2) t is measured respectively ₀, t ₁, t ₂, t ₃, t ₄, t ₅, t ₆the voltage responsive value E of each correspondence that moment dipulse current signal produces ₀, U ₁, U ₂, U ₃, U ₄, U ₅, U ₆and corresponding first order derivative dE ₀/ dt ₀, dU ₁/ dt ₁, dU ₂/ dt ₂, dU ₃/ dt ₃, dU ₄/ dt ₄, dU ₅/ dt ₅, dU ₆/ dt ₆;

(3) utilize the electric capacity on the electromotive force of source of different formulas calculating accumulator, accumulator plate and resistance, and then calculate accumulator capacity:

1) electric capacity on accumulator plate is averaged by three calculating, and calculation equation is:

$C_1=\frac{I}{{\mathrm{dU}}_1/{\mathrm{dt}}_1}$ Equation one

In formula: C ₁represent t ₁electric capacity on moment accumulator plate, I represents the amplitude of current impulse;

$C_2=\frac{I}{\frac{{\mathrm{dU}}_2}{{\mathrm{dt}}_2}-\frac{{\mathrm{dU}}_3}{{\mathrm{dt}}_3}}$ Equation two

In formula: C ₂represent t ₃electric capacity on moment accumulator plate, I represents the amplitude of current impulse;

$C_3=\frac{I}{\frac{{\mathrm{dU}}_5}{{\mathrm{dt}}_5}-\frac{{\mathrm{dU}}_4}{{\mathrm{dt}}_4}}$ Equation three

In formula: C ₃represent t ₅electric capacity on moment accumulator plate, I represents the amplitude of current impulse;

By the result of calculation of equation one, equation two and equation three, get its mean value:

C=(C ₁+ C ₂+ C ₃)/3 equation four

The electric capacity C on accumulator plate accurately can be obtained according to equation four;

2) calculation equation of the resistance on accumulator plate is:

$R=\frac{U_3-U_4}{I-(\frac{{\mathrm{dU}}_2}{{\mathrm{dt}}_2}-\frac{{\mathrm{dU}}_4}{{\mathrm{dt}}_4})\×C}$ Equation five

3) variable quantity of the electromotive force of source of accumulator is averaged by secondary calculating, and equation is:

${\mathrm{\ΔE}}_1=U_2-U_1-(I-\frac{{\mathrm{dU}}_2}{{\mathrm{dt}}_2}\×C)\×R$ Equation six

In formula: Δ E ₁represent t ₁moment is to t ₂the variable quantity of the electromotive force of source of moment accumulator;

${\mathrm{\ΔE}}_2=U_6-U_5-(\frac{{\mathrm{dU}}_5}{{\mathrm{dt}}_5}-\frac{{\mathrm{dU}}_6}{{\mathrm{dt}}_6})\×C\×R$ Equation seven

In formula: Δ E ₂represent t ₅moment is to t ₆the variable quantity of the electromotive force of source of moment accumulator;

The result of calculation of equation five and equation six is got its mean value:

$\mathrm{\ΔE}=\frac{{\mathrm{\ΔE}}_1+{\mathrm{\ΔE}}_2}{2}$ Equation eight

The electromotive force of source variation delta E of accumulator accurately can be obtained according to equation eight;

(4) calculating accumulator capacity:

$\mathrm{SOC}=\frac{E_0+2\mathrm{\ΔE}-U^{*}+\mathrm{\ΔU}}{\mathrm{\ΔU}}$ Equation nine

In formula: SOC represents accumulator capacity, E ₀represent the initial electromotive force of accumulator, i.e. t ₀the magnitude of voltage that moment surveys, U ^*represent the specification voltage of accumulator, the variable quantity of its electromotive force of source when Δ U represents that accumulator becomes sky electricity from Full Charge Capacity, its expression formula as shown in the formula:

$\mathrm{\ΔU}=\frac{\mathrm{\ΔE}\×\mathrm{AH}}{I\×T}$ Equation ten

In formula: AH represents the specification capacity of accumulator, and I represents the amplitude of dipulse current signal, and T represents the pulse width of dipulse current signal.